Dimeric Tetracenomycin Derivatives from a Taklamakan Desert-Derived Streptomyces sp. HDN154193.

Bitetracenomycin A ( 1 ) and its diastereomers [(±)-bitetracenomycin B, (±)- 2 ] were discovered from the cultures of Streptomyces sp. HDN154193. Compounds 1 and (±)- 2 were the first tetracenomycin dimers obtained from a natural source with sp 3 methine protons at the bridge positions (C-12/12'), which also exhibited broad-spectrum antibacterial activity. The racemate (±)- 2 was semisynthesized and separated into enantiomers (+)- 2 and (-)- 2 , and the absolute configurations were determined by specific rotation and ECD data. These metabolites exhibited potent antibacterial activity especially against drug-resistant strains (MRSA and MRCNS) with MIC values ranging from 1.0 to 1.9 μg/mL.